Friedrich the Usurper

Friedrich the Usurper (1289-) was

Early life and background
Friedrich was born in Vienna, Austria in 1289, the second son of King Albert I of Germany and Elizabeth of Carinthia, and a member of the German House of Habsburg. His siblings included Leopold von Habsburg (the Templar grand master).

Duke of Austria
Friedrich inherited the Duchy of Austria upon his father's death in 1308, and he became a subject of Emperor Henry VII of Germany. On 16 January 1309, Duke Friedrich married Adelheid von Nassau, the daughter of the late Adolf of Germany, taking his first wife.